161581687061 has 12 divisors (see below), whose sum is σ = 170554802400. Its totient is φ = 153058339368.

The previous prime is 161581687027. The next prime is 161581687063. The reversal of 161581687061 is 160786185161.

It is not a de Polignac number, because 161581687061 - 2²² = 161577492757 is a prime.

It is a super-2 number, since 2×161581687061² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161581687063) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3492800 + ... + 3538758.

It is an arithmetic number, because the mean of its divisors is an integer number (14212900200).

Almost surely, 2^161581687061 is an apocalyptic number.

It is an amenable number.

161581687061 is a deficient number, since it is larger than the sum of its proper divisors (8973115339).

161581687061 is an equidigital number, since it uses as much as digits as its factorization.

161581687061 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55736 (or 55717 counting only the distinct ones).

The product of its (nonzero) digits is 483840, while the sum is 50.

The spelling of 161581687061 in words is "one hundred sixty-one billion, five hundred eighty-one million, six hundred eighty-seven thousand, sixty-one".